Field of the Invention
Embodiments of the present invention generally relate to power conversion and, more particularly, to a method and apparatus for performing power conversion using an interleaved flyback converter with automatic balancing.
Description of the Related Art
A number of switched mode (pulse width modulated) DC-to-DC converter topologies are available in the power electronics arts for performing DC-to-DC conversion. Such converters employ a flyback converter topology which is used in instances that require electrical isolation, voltage boost-up, and high efficiency. A flyback converter topology consists of a transformer, a switch (usually a power MOS FET transistor) and a diode. Typically, the switch is in series with the primary winding of the transformer and the secondary winding the transformer is serially coupled through the diode to a load. By switching a current through the primary coil, the DC voltage applied across the primary coil and switch is “boosted” to a higher voltage level at the load.
In order to double the output power available from a typical DC-to-DC converter, two flyback converters may be connected in parallel and operated in an interleaved fashion. Each of the flyback converters forms a “leg” of the overall DC-to-DC conversion process. Each leg is activated independently and in an interleaved manner. To facilitate a balanced operation such that the power is accurately converted from the input DC to the DC applied to the load, each leg must be “matched”. To be able to exactly split the load in a balanced fashion across the legs and be able to activate one leg while the other leg is completely deactivated, the components of the two converters must exactly match each other. In practical implementations, this is simply not possible, which leads to misbehavior, i.e., activation and deactivation times are not synchronized and the load is not balanced. Such operation can lead to inefficient conversion and, in some instances, damage to the DC-to-DC converter circuitry.
Therefore, there is a need in the art for a method and apparatus for providing power conversion using interleaved flyback converters with automatic balancing.